The University of Colorado Maternal Fetal Medicine Unit (UC-MFMU) is uniquely positioned to be an active and valuable participant in the MFMU Network of the NICHD. The strengths of this proposal include: 1) a mature MFM faculty with a broad range of specific clinical strengths within the subspecialty with leadership and experience in designing and conducting large multicenter trials, 2) a thirty year history of collaboration on research projects and clinical care between the obstetricians and neonatologists at the University of Colorado, 3) a new state of the art Anschutz Medical Campus which houses University of Colorado Hospital, the Children's Hospital, new research facilities and the Colorado Clinical and Translational Sciences Institute which includes the Adult and Perinatal Clinical Translational Research Centers, 4) the Department's basic science division has extensive experience with translational research and access to numerous research cores on the AMC campus, and 5) an exceptionally strong departmental and institutional commitment to participate in MFMU research. The Department of Ob/Gyn has faculty housed at the University Hospital/Anschutz Medical Campus and Denver Health Medical Center which provides the MFMU access to a large ethnically and economically diverse population from which patients can be recruited. The geographic and population diversity represented by our location as one of the very few academic reproductive medicine centers in the Rocky Mountain region is an additional important asset that the UC-MFMU brings to the MFMU Network. This application describes these strengths in detail. This application will present a Concept Protocol entitled A Randomized Clinical Trial of Metformin to Prevent Recurrence of Gestational Diabetes that will reflect the capabilities of the investigators.